Patent Literature 1 (PTL 1) discloses an example of the background art. The communication robot disclosed in PTL 1 has a conversation with a human using a sound. Moreover, the purpose of using the communication robot is to facilitate a conversation between people in a particular space and build a better human relationship.
When detecting two or more people whose distance is within a predetermined value, this communication robot determines that the people are in close proximity to each other, and approaches the people to identify individuals. This enables the communication robot to output by sound, information of common interest among the identified individuals, and to display a text, image, or video in a display.